Wafer box and photo mask box

ABSTRACT

A check valve disposed inside a semiconductor device container. The check valve includes a cylinder and a check component. With opening and closing of the check component that is elastic, particles are minimized to prevent polluting objects stored in the semiconductor device container.

FIELD OF THE INVENTION

The invention relates to a semiconductor device container and more particularly relates to semiconductor device container with a check valve. The semiconductor device container may be a photo mask box or a wafer box.

BACKGROUND OF THE INVENTION

Modern semiconductor technology advances rapidly and optical lithography plays an important role therein. Basically, all pattern definitions rely on optical lithography. The application of optical lithography in semiconductor processing is to produce photo masks with specific transparent shapes corresponding to designed circuits. Under exposure theory, a light source exposures specific patterns on a silicon wafer via a photo mask. Because any dust like particles, powder and organic compound may deteriorate quality of projected images, photo masks for defining patterns as well silicon wafers or other semiconductor projectors must be kept absolutely clean. In normal wafer processing, therefore, clean room environment is provided to prevent particle pollution. Today's clean rooms, however, are not absolutely free of dust. Therefore, anti-pollution containers are used in modern semiconductor processing for storing and transmitting photo masks and wafers so as to keep the photo masks and the wafers clean. Anti-pollution semiconductor device containers are also used for storing and transmitting semiconductor devices to keep the semiconductor devices clean.

Semiconductor device containers are used for storing semiconductor devices during semiconductor processing to facilitate moving and transmitting of the semiconductor devices from one machine to another to exclude contact of the semiconductor devices to the air so as to prevent variation of the semiconductor devices due to impurity pollution. Therefore, in advanced semiconductor device factory, photo mask containers and semiconductor device containers are required to be clean so as to satisfy the standard mechanical interface (SMIF), i.e. to satisfy under Class 1 of SMIF. Conventional solutions include filling gas into photo mask containers and semiconductor device containers.

As illustrated in FIG. 1, a check valve is usually used for gas filling and gas exhausting. Such check valve usually has a valve body (a) disposed inside a valve body container (b), a fastener (c), an elastic structure (d) clamped between the valve body (a) and the elastic structure (d) and a filter (e) disposed behind the fastener (c). When the check valve is filled up with gas, the valve body (a) is pressed so that the valve body (a) separated from the valve container (b) to form a passage. Gas flows through the valve container (b) via the passage and enters the container via the fastener (c) and the filter (e) behind the fastener (c). When gas filling is stopped, the pressing on the valve body (a) is stopped. With the elastic structure (d), the valve body (a) is returned back to the valve container (b) to form a close status.

However, after operation many times, the valve body (a) is rubbed with multiple components many times, so it is easy to produce many particles. Particles then pollute photo masks and wafers stored in the containers, and therefore containers may be required to throw away, which results in increasing manufacturing cost. Therefore, it is important to provide a gas filling equipment that does not generate contamination.

It is therefore provided the invention to improve the check valve of photo mask containers and wafer containers to solve the aforementioned problems.

SUMMARY OF THE INVENTION

In order to solve the aforementioned problem, a major objective of the invention is to provide a check valve disposed in a wafer box by opening and closing a single elastic component to prevent generation of too much particles that may pollute wafers stored in the wafer box.

According to the objective, the invention provides a wafer box majorly including a box body. An opening is formed in a lateral surface of the box body. A door body is engaged to the opening for forming a container space for storing a wafer. The features of the wafer box include configuring at least one pair of check valves. Each check valve includes a cylinder and a check component. The cylinder is a hollow cylinder and the check component is disposed inside the cylinder. The check component includes a circular dome body having an uplifted top and a circular bottom, a circular ring formed and surrounding the circular bottom, and at least one cutting line extending from the center of the uplifted top to the circular bottom.

Another objective of the invention is to provide a check valve disposed in a photo mask box by opening and closing a single elastic component to prevent generation of too much particles that may pollute photo masks stored in the photo mask box.

According to the objective, the invention provides a photo mask box majorly including a top cover and a bottom cover. The top cover and the bottom cover are engaged to form a container space for storing a photo mask. The features of the photo mask box include configuring at least one pair of check valves disposed inside the photo mask box. Each check valve includes a cylinder and a check component. The cylinder is a hollow cylinder and the check component is disposed inside the cylinder. The check component includes a circular dome body having an uplifted top and a circular bottom, a circular ring formed and surrounding the circular bottom, and at least one cutting line extending from the center of the uplifted top to the circular bottom.

With the design of the present invention, particles are prevented during gas filling and gas exhausting of the wafer box and the photo mask box so as to prevent polluting the semiconductor devices stored in containers.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a conventional check valve;

FIG. 2 is a diagram illustrating an embodiment of a check valve according to the present invention;

FIG. 3A is a diagram illustrating gas filling of a check component embodiment according to the present invention;

FIG. 3B is a diagram illustrating stopping of gas filling of the check component embodiment according to the present invention;

FIG. 4 is a diagram illustrating a check valve being installed in a wafer box according to the present invention; and

FIG. 5 is a sectional diagram of a check valve installed in a photo mask box.

EMBODIMENTS OF THE INVENTION

The present invention relates to a check valve and more particularly relates a check valve disposed in a wafer box and a photo mask box. In such check valves, certain elastic materials and filter membranes are implemented by using conventional techniques, and therefore would not be explained with detail. Besides, the drawings mentioned in following disclosure are used for exemplifying the concept of the invention, and therefore the dimensions of components in these drawings are not accurate for actual implementations.

Please refer to FIG. 2, which illustrates an embodiment of a check valve according to the present invention. As illustrated in FIG. 2, the check valve 1 comprises a cylinder 10 and a check component 20. The cylinder 10 is a hollow cylinder and the check component 2 0 is disposed inside the cylinder 10. The check component 20 comprises a circular dome body 201 that has an uplifted top 2011 and a circular bottom 2013, a circular ring 203 being formed and surrounding the circular bottom 2013, and at least one cutting line 205 extending from the center 2015 of the uplifted top 2011 to the circular bottom 2013. In this embodiment, there are multiple cutting lines 205 with straight line shapes and the cutting lines 205 are symmetrical to each other for each two of the cutting lines 205. In this example, there are three pairs of the cutting lines 205, but the shape and number of the cutting lines 205 may be varied without limitation to the present invention. The check component 20 may be an elastic material such as a fluoroelastomer, silicone, rubber or the like. The material may also be varied without limitation to the invention.

In addition, a filter membrane 30 is disposed above the check component 20 and inside the cylinder 10. The filter membrane 30 has a microporous structure for filtering dust and impurity of gas. The material of the filter membrane may be polytetrafluoroethene (PTFE) but other materials may also be used under the invention.

Next, please refer to FIG. 3A, which illustrates an embodiment of the present invention by filling gas. As illustrated in FIG. 3A, when the check valve 1 is used to fill up with gas, the gas enters from the end (A). The fluid pressure struts and opens valves 207 (N cutting lines forming 2N valves, where N is an integer equals or larger than 1) formed by at least one cutting line 205. A passage 209 formed by the opened valves 207 allows gas to enter. The gas passes through the passage 209 and is filtered by the filter membrane 30. Then, the gas reaches the end (B) of the check valve 1 for filling up with the gas.

Next, please refer to FIG. 3B, which illustrates an embodiment of the invention with stopping filling gas. As illustrated in FIG. 3B, when filling gas is stopped, the valves 207 are made by resilient material so as to be restored to a close status in which each valve 207 is restored for closing the passage 209. Because the check component 20 is of a dome shape and has a certain thickness, the pressure of the inner gas make the valve 207 to move in opposition of the passage is not easy which can prevent gas flowing backward.

In an embodiment of the invention, the check component 20 has a diameter of 13 mm and the valve 207 (of the check component) has a thickness of 1.5 mm. When the check component 20 is larger, its thickness is also increased relatively, but the ratio between the diameter and the thickness may still be changed under the scope of the invention. Besides, the check valve 1 of the invention may also be used in liquid or other fluid. The type of the fluid may also be changed and still under the scope of the invention.

Please refer to FIG. 4, which illustrates a check valve installed in a wafer box. As illustrated in FIG. 4, a wafer box 4 basically comprises a box body 40. An opening 401 is formed in a lateral surface of the box body 40. A door body 42 is engaged to the opening 401 to form a container space for storing a wafer. A pair of check valves 1 is disposed at the bottom 403 of the wafer box 4. The pair of check valves 1 comprises a gas filling valve 4031 and a gas exhausting valve 3033. Because the check valve 1 allows the gas flowing in one-way, the check components 20 inside the check valve 1 of the gas filling valve 4031 and the gas exhausting valve 4033 are arranged upside down to each other.

Usually, inside of the wafer box 4 is filled with inert gas to protect wafers stored therein. Therefore, after a while, the gas inside the wafer box 4 needs to be exchanged. When exchanging the gas, the gas filling valve 4031 is filled up first, and then the gas exhausting valve 4033 is exhausted so as to replace the inner gas with new gas. Please be noted that the arrangement positions of the gas filling valve 4031 and the gas exhausting valve 4033 as well as their numbers may be varied while still under the scope of the invention.

Please refer to FIG. 5, which is a sectional diagram illustrating a check valve installed in a photo mask box. As illustrated in FIG. 5, the photo mask box 5 comprises a top cover 50 and a bottom cover 52. The top cover 50 is engaged with the bottom cover 52 for forming a container space for storing photo masks. A pair of check valves 1 is disposed in the bottom cover 52 of the photo mask box 5. The pair of check valves 1 comprises a gas filling valve 521 and a gas exhausting valve 523. Because any of the check valves 1 allows gas passing in one-way only, the check components 20 of the check valve 1 of the gas filling valve 521 and the gas exhausting valve 523 are arranged upside down to each other.

Usually, inert gas is filled up in the photo mask box 5 to protect photo masks stored therein. Therefore, after a while, the gas inside the photo mask box 5 needs to be exchanged. When exchanging the gas, the gas filling valve 521 is filled first, and then the gas exhausting valve 523 is exhausted so as to replace the inner gas with new gas. Please be noted that the arrangement positions of the gas filling valve 521 and the gas exhausting valve 523 as well as their numbers may be varied while still under the scope of the invention.

The foregoing descriptions of embodiments of the present invention have been presented only for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art. Additionally, the above disclosure is not intended to limit the present invention. The scope of the present invention is defined by the appended claims. 

What is claimed is:
 1. A wafer box comprising a box body, an opening formed in a lateral surface of the box body, and a door body engaged to the opening for forming a container space for storing a wafer, which is characterized in that: at least one pair of check valves disposed inside the box body, each check valve comprising a cylinder and a check component, the cylinder being a hollow cylinder and the check component being disposed inside the cylinder, wherein the check component comprises: a circular dome body having an uplifted top and a circular bottom; and at least one cutting line extending from a center of the uplifted top to the circular bottom.
 2. The wafer box of claim 1 further comprising a filter membrane disposed inside the cylinder of the check valve.
 3. The wafer box of claim 1, wherein the check valve is disposed at a bottom inside the box body.
 4. The wafer box of claim 1, wherein the pair of check valves comprises a gas exhausting check valve and a gas filling check valve.
 5. The wafer box of claim 1, wherein the circular dome has a thickness.
 6. The wafer box of claim 1 further comprising a circular ring surrounding the circular bottom.
 7. The wafer box of claim 1, wherein the at least one cutting line is multiple cutting lines and is set symmetrically to each other for each two of the cutting lines.
 8. The wafer box of claim 1, wherein each of the check valves is an elastic material.
 9. The wafer box of claim 8, wherein the elastic material is fluoroelastomer, silicone or rubber.
 10. A photo mask box comprising an upper cover and a bottom cover, the upper cover being engaged with the bottom cover to form a container space for storing a photo mask, which is characterized in that: at least one pair of check valves is configured, each check valve comprising a cylinder and a check component, the cylinder being a hollow cylinder and the check component being disposed inside the cylinder, wherein the check component comprises: a circular dome body having an uplifted top and a circular bottom; and at least one cutting line extended from a center of the uplifted top to the circular bottom.
 11. The photo mask box of claim 10, wherein each of the check valves further comprises a filter membrane disposed inside the cylinder of the check valve.
 12. The photo mask box of claim 10, wherein the check valve is disposed inside the bottom cover.
 13. The photo mask box of claim 10, wherein the pair of check valves includes a gas exhausting valve and a gas filling valve.
 14. The photo mask box of claim 10, wherein the circular dome body has a thickness.
 15. The photo mask box of claim 10, further comprising a circular ring surrounding the circular bottom.
 16. The photo mask box of claim 10, wherein the at least one cutting lines comprises multiple cutting lines and is set symmetrically to each other for each two of the cutting lines.
 17. The photo mask box of claim 10, wherein each of the check valves is an elastic material.
 18. The photo mask box of claim 17, wherein the elastic material is fluoroelastomer, silicone or rubber. 